1. Field of the Invention
The present invention is directed to a nozzle plate which comprises a plurality of nozzle openings for an ink recording head or mosaic printing unit which has ink channels arranged in a mosaic pattern extending away in straight lines from outlet openings of the head.
2. Prior Art
If one arranges several ink channels inside a recording head for a mosaic ink recording device, it is necessary to seal these ink channels at their outlet point or opening by a nozzle plate. According to the arrangement of the ink channels, this nozzle plate is provided with nozzle openings, which serve to align the ejected ink droplets in accordance with the desired direction of flight. German Offenlegungsschrift No. 2,543,451 discloses an embodiment of a nozzle plate in which the nozzle channels of the plate are cylindrical bores that are arranged parallel to each other as they extend through the nozzle plate. In addition, U.S. Pat. No. 3,683,212 discloses a pulse drop ejector in which each channel is sealed by a jewel which is provided with a thin cylindrical bore. This jewel is a clock or watch jewel bearing, whose inside is hemispherical in order to achieve a stability which is necessary in view of the thin walls.
When nozzle plates of this type having cylindrical bores are used, high overall operating voltages are necessary for the drive elements in order to achieve the speed of flight for the ink droplets which is necessary for a distorsion-free type face. These high operating voltages result from the flow losses in the cylindrical nozzle bores.